Centrifugal amalgamator



Oct. 14. .1924- H. N. BANKS ET AI.

CENTRIFUGAL AMALGAMA'TQR Filed April 27. 1923 2 Sheets-Sheet. l

Swl- 8 /NVENTORs H. N. BANKS ET AL CENTRIFUGAL AMALGAMATOR Filed April 27. 192:5 2 sheets-sneu 2 INVENTOR ATTORNEY Patented Got. 14, 1924.

UNITED STATES HAB-OLD N. BANKS AND GEQRG-E E.

BANKS, OF EVERETT, WASHINGTON.

CENTRIFUGAL AMALGAMATOR.

Application filed April 27, k1923. Serial No. 635,154.

To all whom z5 may concern.'

Be it known that we, HAROLD N. BANKS and GEORGE E. BANKS, citizens of the United States, residing at Everett, Snohomish County, State of 1Washington, have invented certain new and useful Improvements in Centrifugal Amalgamators, of which the following is a specification.

This invention comprises certain novel improvements in centrifugal machines of the class designed for the recovery of gold and platinum and other precious metals from placer sand and placer gravel and black sand and crushed-ores.

The invention involves a type ofv machine quite similar to that presented in our application Serial No. 508,555, iiled Oct. 8, 1921.

However, note the change in the size, shape and placement of the riilles in the bowl.

Figure 1 is a quarter sectional view of the machine.

Figure 2 is a sectional view of the bowl, showing the riies 20.

Figure 3 shows a cross-section of shaft 9, with the key-way 32.

Figure L1 is the key that fits into 32 as shown at 31.

The base 1 and shaft 9 and frame 17 are of cast iron and steel.

The bowl 19 is cast aluminum, the trough a is galvanized iron.

The shaft, carrying the bowl, rests on a suitable ball bea-ring at 7 and 8 and is held in place by bolts and shoulders 2, 3, 1, 5.

The shaft 9 is held in place at 11 in a suitable ball race, 12, 13, 14, by the frame, which attaches to the four sides of the iron base in a braced manner and holding the bowl from vibrating while revolving, the frame being bolted to the base at 18.

The braces 27 carrying the trough are of `angle iron and bolted to the frame at 16 and to the trough at 24.

The bowl 19 is round, with saucer shaped bottom and perpendicular walls 21.

The trough d encircles the bowl with a double wall, the inside wall c depending under the outer rim of the bowl to catch the over-flow of waste matter, at bottom of the walls d and c is a slanting bottom e which afords an out-flow to discharge pipe 28.

The over-How lap of the trough 26 is bolted to outside of trough d at 25.

The bowl has a projecting rim 22 that overlaps the inside of trough to carry the waste matter over and free from the bowl into the trough.

The inner wall of the bowl has rigid, square cornered riiiies, projecting at right angles to the sides.

rThe lower riflie projects inward towards the centre of the bowl a measurement of twice that of the upper riiiie, the intermediate riffles project to a line drawn taut with the edge of the upper riiile and lower riflle, making a slight outward-upward throw of the contents of the bowl, which aids in the elimination of the waste material, such as sand, gravel, dirt and water, after the gold and platinum and other precious metals are recovered.

The bowl may be fastened to the shaft 9 by a key and screws 29, 30, 31, with double security against working loose by vibration while in operation.

The rim 22 projects slightly inwardly, acting as a riflie, allowing a yfree flow of the discharge matter, and yet retarding and catching any particle and speck of gold and amalgam that by accident in adhering to a speck of sand, may be carried to the top of the bowl, preventing it from being thrown into the trough 23 and carried away through discharge pipe 28.

Suitable power to rotate the bowl is applied to the pulley 10.

A, sufficient charge of mobile mercury to fill the spaces between4 the three or more lower riiiies, flush with the projecting edge of each riiile, is placed in the bowl, this mercury forms a cushion with mirror effect and is held in the spaces by the centrifugal force of the bowl and does not flour.

In operating the machine, a large funnel 33 is suspended above the bowl, into which the feed of gravel, sand, dirt and water, after being thoroughly mixed to a thin consistency, to allow of a very thin flow up the sides of the bowl, is supplied by means of a trough or revolving mixer, or other suitable appliance. The small and lower end of the funnel is inserted into the bowl and extends downward to near the bottom at 19 at the centre. This affords a head pressure of considera-ble force and aids very much in forcing the waste material, in conjunction with the centrifugal force of the bowl, from th'e bowl and over the. rim, where it is emptied into the trough and then down and out the discharge pipe, the said pipe is elongated to reach to near the ground and has a siphonic force and effect, to keep the bowl free and clear of the' waste matter, after the values have been recovered by the mercury.

When the feed leaves the funnel and touches the ybottom of the bowl it is thrown to the side by the centrifugal force and the pressure of the intake pipe, and the gold having more specific gravity is separated from the gravel and water and sand and is forced into contact with the mercury cushion under the riflies, where it is amalgamated, whiley the platinum, bein@P heavier than the gold or mercury, is forced through the mer cury cushion to the walls of the bowl and is there held by the centrifugal force and cushion of mercury .untilv removed by the operator.

The speed of the bowl is lnot great, as the more moderate speed doesthe best work. A

high speed has the tendency to cause vthe water and-sand and gravel to flow in parallel lines to the riflles instead of upward and over the rim of the bowl, resulting in a slight disposition to clog the bowl with sand and gravel, instead of keeping it free and clear, as the slower motion does.

Upon the Vstopping' of the bowl, the mercury and amalgam flow to the center of the bottom of the bowl, from where it is removed with any suitable tool or appliance.

With the perpendicular sides of the bowl and the rigid and right-angled, square edged rilfles, the mercury cannot and does not flow over the top of the bowl, nor escape in any manner, and is recovered in its whole weight.

The bowl is cast aluminum because that metal does not attract magnetic sand like a steel bowl would do, and aluminum does not hold mercury like` copper bowl would.

le claim:

A rotatable bowl cast in aluminum, provided with saucer bottom, .perpendicular sides and open top and rigid, squarecornered riflles, projecting inward at rightf anffles to the inner" sides of the bowl said rites projecting in different measurements of projection to form a slight, slanting,out

ward and upward formation, the measure-` ment between the opposite side `ofupper rilile being greater than the measurementbetween the opposite side of lower riflle across the diameter of the bowl, a rim around and onl top of the bowl, projecting inwardly to furnish a narrow riitlle and projecting outward to afford easy outward flow of the waste matter into a discharge pipe or trough.

`HAROLD NQBANKS. GEORGE E. BANKS.

Vitnesses C. W. JORDAN, G. H. WILSON. I 

